Method of making negatives



Patented Jan. 29, 1929.

UNITED STATES PATENT OFFICE.

WILIIIAM HEINECKE, OF CHICAGO, ILLINOIS.

METHOD OF MAKING NEGATIVES.

No Drawing.

faces or photo-engravers plates and the like,

as used in photo-mechanical printing processes, in which the printingsurface has to be made sensitive to light in order to receive and holdthe image conveyed upon same from the negative, photographically.

According to my new method, an impression is pulled or taken on a sheetof sensitized photographic paper, film, stripfilm, glass plate or thelike, from engravings or transfers on lithographic stone, or steel,copper or zinc plate or the like, or from type composition, electrotypeplates and the like,

or from inked transfers on rubber blankets v or transfer paper orsimilar transfer mediums, or from the fingers of a person forfingerprinting purposes, by means of. printing ink or some othersubstance suitable for the purpose of protecting those portions of thesensitized film, paper, etc., covered with the ink against the chemicalaction of the reducing or developing agent, contained in the developingsolution, on the silver-halids or other sensitizing agents used in thesensitized material. As the purpose of the inked impression is not toprotect the portions covered with the ink or other suitable substance,

against the action of the light, but only against the contact with thechemicals contained in the developing solution and against the chemicalaction of same, it is not essential whether the ink, or other substanceused for making the impression, is pigmented or not. It is, however,essential that the ink possesses properties which will aid in resistingsapomfication, or dissolution by the developing agents used. Afterdeveloping, the negative is transferred to a fixing, bath and afterrinsing to a bath in a solvent which will remove the ink, as, forexample, a saturated solution of potassium bicarbonate, whereupon thenegative is placed back into the fixing solution, after which it iswashed, dried and ready for use. The above description of themanipulation refers more par- Application filed May 6, 1927. Serial No.189,458.

ticularly to the use of photographicmaterial sensitized withsilver-halide by way of illustrating the method. The composition of thedeveloping agents, fixing agents and solvents used for removing the inkwill vary accordingto the chemical composition and properties of thesensitizing agents and ink.

The whole operation can be performed in daylight which constitutes animportant factor in the practical application of the process and itsoperation in printing plants for the reason that it requires no darkroom or safelight, and obviates the otherwise almost insurmountabledifficulties of removing to or installing machinery for pullingimpressions in a dark room, or operating presses in safelight. Thefurther object of this process is to preserve a faithful negative ofprinted or transferred impressions for indefinite further use.

In order to make a negative by this new direct method, I proceed asfollows:

At first, I make an impression from engravings on copper plate, steelplate and the like, or from engravings or transfers on lithographicstone or zinc plate and the like, or from electrotype plates, linotypeor other composition, or from transfers on rubber blankets,transfer-paper or similar transfer mediums, on a .sensitized sheet ofphoto graphic paper or film, or stripfilm, or glass plate, tho, ifdesired, the impression can also be made by drawing. This impression canbe made by means of printing ink or some other substance, pigmented orunpigmented, the only requirements being that this printing element isviscous and resists the action of weak alkali solution. Thereupon, thesheet of paper or film, stripfilm or dryplate isplaced into a developingsolution and devel-- oped until the entire surfaceacquires the desireddensity.

For the developer, I preferably use the following formula:

, Oz. Water -l 32 Sodium sulphite, 'dry 3 I-Iydrochinon 1 Formalin 1 ormodifications of same, according to the results desired. After thedeveloping, I thoroughly rinse the negative in water, whereupon I placesame in a plain sodium thiosulphate bath, modifying same, whennecessary, according to the requirements of the photographic materialused. From the fixing bath,

venting soiling trays and hands of the operator and covering the fixingbath with an oily film or otherwise affecting same unfavorably. From thesolvent, the negative is retrans ferrcd to the fixing bath, washed anddried,

, and is then ready for use.

The word film in the claims is used in a generic way to comprise allkinds of sensi- 'tized material, including paper and glass plates. Theword ink in the claims is used in a generic Way to comprise all kinds ofsubstances suitable for making an impression or transfer for the purposeof protecting those portions of the sensitized surface, covered with theimpression or transfer and forming the image, against the chemicalaction of the developing solution and its alkaline, or acid components.Also the Word develop in the claims is used in a generic way to compriseall kinds of reducing agents reacting with the various possiblesensitizing agents, as, for instance, silver-halids or ferric compounds,which are used to produce photographically a visible image. Likewise,the word sensitize in the claims is used in a generic way to compriseall kinds of emulsions, solutions and compounds used for photographicpurposes and capable of undergoing such chemical changes under theaction of light as an assistant factor as to produce an image, known inphotography under the term of negative and by means of the contrast ofthe clear and opaque portions constituting the image as result ofexposure to light and chemical action of the reducing agents.

I claim:

-1. The method of making a negative for use in photo-mechanical printingprocesses and photographic purposes, which consists in making animpression on a sensltized member, developing said member, and removingand hoto ra )hic ur oses which consists in making an impression on asensitized member, developing said member, then fixing it, then removingthe impression, and finally fixing said member.

4. The method of making negatives for use in photo-mechanical printingprocesses and photographic purposes, which comprises making impressionson a sensitized film, placing the same in a developing bath comprisingwater, sodium sulphite, hydrochinone and formalin, rinsing, removing theink, and final- 1y fixing the film in a hypo bath, for the purpose ofproducing a negative.

5. The method of making negatives for use in photo-mechanical printingprocesses and photographic purposes, which comprises making impressionson a sensitized film, placing the same in a developing bath comprisingwater, sodiumsulphite, hydrochinone and formalin, rinsing, removing theink by means of a solvent, and finally fixing the film in a hypo bath,for the purpose of producing a negative.

6. The method of making negatives for use in photo-mechanical printingprocesses and photographic purposes which comprises making impressionson a sensitized film, placing the same in a developing bath comprisingwater, sodium sulphite, hydrochinone and formalin, rinsing, removing theink by means of potassium bicarbonate, and-finally fixing the film in ahypo bath, for the purpose of producing a negative. V

In testimony whereof I affix my signature.

- WILLIAM HEINEOKE.

